Body odor of the human body, etc. is evolved by indigenous dermal bacteria that decompose secreta from sweat glands or sebaceous glands. Generally, as indigenous dermal bacteria, bacteria of the genus Micrococcus and the genus Staphylococcus which are Gram-positive cocci, and bacteria of the genus Corynebacterium, the genus Propionibacterium and the genus Brevibacterium which are Gram-positive rods and coryneform bacteria (polymorphic type), are known, and it is known that bacteria causing odor of the armpit, which is particularly a problem, are coryneform bacteria. The main components of the decomposition products due to such indigenous dermal bacteria are fatty acids having a carbon number of not more than 10, such as acetic acid, propionic acid, isobutyric acid, isovaleric acid, caproic acid and capric acid.
As conventional methods for removing or deodorizing such a body odor, suppressing the body odor by a bactericide or an antisweat agent or masking the body odor by an aromatic is performed. However, with respect to the conventional bactericides, the minimum use thereof is desired from a problem of safety in the human body, and also with respect to antisweat agents, the use thereof is limited only to application to specific local areas because it suppresses important physiological function of the human body. Therefore, for example, at a portion such as the armpit, where sweat and sebum are secreted and indigenous dermal bacteria are likely to grow, it is difficult to sufficiently prevent body odor. Further, masking body odor by an aromatic is likely to cause malodor by mixing of the smell of the aromatic and the body odor.
In order to solve such problems, some antibacterial agents safe to the human body are proposed. For example, in JP-A-SHO 61-291503, an antibacterial/anticultural agent, whose active ingredient is a mixture of the sap of yucca and an acid such as acetic acid or propionic acid, is proposed. However, because acetic acid or propionic acid itself is a component evolving malodor of the body odor, such an agent is not always practical.
In JP-A-SHO 60-42765 and JP-A-HEI 2-40043, an antibacterial agent, which contains natural farnesol and a synthetic farnesol as its active ingredients, is disclosed. Although these active ingredients are efficacious against bacteria of the genus Staphylococcus, they are weak in antibacterial properties against bacteria of the genus Corynebacterium, and data of antibacterial property to other indigenous dermal bacteria such as bacteria of the genus Propionibacterium are not disclosed.
Further, in JP-A-HEI 8-40861, a method for preventing and treating the foot odor using a monoglycerine ester of a middle chain fatty acid is proposed. Even in this method, because a component evolving malodor such as caprylic acid or capric acid is generated from the monoglycerine ester of the middle chain fatty acid by lipase action caused by indigenous dermal bacteria, it is not always practical.
Pimples are a dermal disease expressed mainly in puberty and the disease is called acne, and clinically they are defined as "chronic inflammatory variation generating in pores around the hair follicle fatty gland". Although pimples are a dermal disease caused by complicatedly entangled factors, generally it is considered that excessive secretion of sebum, cornification of hair follicles and bacteria in hair follicles have an important function therefor.
It is known that bacteria causing pimples are Propionibacterium acnes which are coryneform bacteria. The bacteria grow in trichocyte, produce lipase and hydrolyze triglyceride which is a major component in sebum, thereby producing free fatty acid and causing local inflammation. This is considered to be a main reason for generation of pimples.
As conventional methods for preventing or treating such pimples, suppression of secretion of sebum by female sex hormones, sterilization by antibiotics etc. and breakaway of keratin by sulfur etc. are conducted. However, there is a fear of side effects in use of female sex hormones, in use of antibiotics there is a fear which also breaks a microbial flora on derma useful to the human body, and in use of sulfur there is a problem in stimulation of derma and generation of sulfur smell.
From such circumstances, development of safe antibacterial agents which can suppress the growth of indigenous dermal bacteria and suppress the evolution of body odor even in a portion where sweat or sebum is much secreted in the human body, and development of safe antibacterial agents which are efficacious in suppressing the body odor and preventing and treating pimples without breaking microbial flora of indigenous dermal bacteria by preferentially suppressing coryneform bacteria which cause the armpit odor or pimples, are required.